The invention relates generally to RFID readers. More specifically, the invention relates to an RFID reader with an antenna array and an antenna switching unit for selectively coupling or decoupling the antennas in the antenna array.
Identifying and tracking assets is a considerable expense for any business that handles significant volumes of inventory. For example, inventory items that are brought to a storage facility must be identified, categorized and stored so that the items can be readily retrievable, while inventory items that are to be shipped from storage must again be identified to provide an accurate accounting of items remaining in storage. Additionally, entire inventories may need to be periodically recounted to ensure that accounted inventory levels remain accurate over time despite occasional human error. Thus many man-hours of labor may be consumed just in asset tracking alone. Similarly, in shipping applications, large quantities of different items may need to be counted, listed, checked, and manifests or declarations may need to be generated for the shipper, receiver, and customs authorities.
Recent developments in Radio Frequency Identification (RFID) technology may make it possible, however, to greatly decrease the cost of asset tracking. RFID technology utilizes a circuit known as an RF tag, which is capable of carrying a small amount of identification data related to an item to which it is attached. To identify an item, an RF tag reader transmits an RF signal to an RF tag. The RF signal powers the RF tag, inducing the RF tag to transmit a return signal that carries the identification information embedded on the RF tag. By automating most of the asset tracking process, RFID technology can provide a quicker, more accurate and less expensive method of tracking assets.
However, current RFID techniques may not be suitable for certain applications. For example, international RF spectrum regulations often vary greatly, meaning that certain RFID tags may not be usable in all of the countries to which assets might be delivered. Additionally, certain RFID tags may not operate reliably when used with assets that include a number of small metal items. Furthermore, LF (Low Frequency) RFID tags are generally directional and operate over relatively short distances, compared to higher frequency RFID tags.
It may be advantageous, therefore, to provide an RFID tag reading system that is compatible with international RF spectrum regulations, operates effectively over a significant reading range and can read RF tags oriented in any reading direction.